I have a product based on the PIC18F4580. It works well with RS-232, RS-485=
 and SDI-12. But I have one application at 4000 meters of altitude where th=
e EEPROM settings are getting corrupted at unusual times. Once the EEPROM i=
s wiped, I loose contact with the unit. There is a 5V LDO regulator. This a=
pplication has a radio with 1/10W output. The case is just aluminum. The an=
tenna is a 3db omni that is about 5cm from the PC board. The ambient temper=
ature did not drop below -29C this past winter. The PIC18F4580 is rated for=
 -40. I can't believe the radio would cause this problem. Out of 40 station=
s, 15 were made non-functional because the address, baud rate, communicatio=
n mode are all stored in EEPROM. Power is turned on every hour for 40 secon=
ds by a data logger with RTCC. I have hundreds of these units in remote are=
as using RS-232 with no problems. I use the same UART for all communication=
 modes. I use the same command parsing and EEPROM Read/Write for all modes.=
 I just enable!
  the appropriate IC for the mode. The 40 stations all use the SDI-12 commu=
nication. I ran it in the office for weeks without issue.=20

I would like to hear about any theories on why this is happening.=20

Thank you to the PICList=20

Best Ragards,=20

Zipwize=20
--=20
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